On 13/07/12 12:52, Johannes Pfau wrote:
Am Fri, 13 Jul 2012 11:53:07 +0200
schrieb Don Clugston <d...@nospam.com>:
On 13/07/12 11:16, Johannes Pfau wrote:
Casting from void[] to ubyte[] is currently not allowed in CTFE. Is
there a special reason for this? I don't see how this cast can be
dangerous?
CTFE doesn't allow ANY form of reinterpret cast, apart from
signed<->unsigned. In particular, you can't do anything in CTFE which
exposes endianness.
It might let you cast from ubyte[] to void[] and then back to ubyte[]
or byte[], but that would be all.
So that's a deliberate decision and won't change?
I guess it's a safety measure as the ctfe and runtime endianness could
differ?
Yes.
Anyway, I can understand that reasoning but it also means that
the new std.hash could only be used with raw ubyte[] arrays and it
wouldn't be possible to generate the CRC/SHA1/MD5 etc sum of e.g. a
string in ctfe. (Which might make sense for most types as the result
could really differ depending on endianness, but it shouldn't matter for
UTF8 strings, right?)
Maybe I can special case CTFE so that at least UTF8 strings work.
BTW: casting from void[][] to ubyte[][] seems to work. I guess this is
only an oversight and nothing I could use as a workaround?
Probably a bug.
But you can convert from char[] to byte[]/ubyte[]. That's OK, it doesn't
depend on endianness.
